Our group is participating in a prospective double-blind cooperative study designed to assess the efficacy of several drugs in the long-term therapy of men with evidence of documented myocardial infarction. The ability of these drugs to reduce the mortality rates in such men will serve as the primary endpoint. Secondary endpoint such as recurrent myocardial infarction and cerebrovascular accidents will also be studied. All the drugs proposed for evaluation have been reported to influence serum cholesterol-lipid-lipoprotein levels. The relationship between drug effects on clinical events and serum lipids will be evaluated. In addition, the efficacy of aspirin in reducing mortality and secondary endpoints is being evaluated in a group of men with documented myocardial infarction.